Search results for "Saccharomyce"
showing 10 items of 875 documents
Chromatin structure of the yeast SUC2 promoter in regulatory mutants
1992
We have previously suggested that two positioned nucleosomes are removed from the promoter of the Saccharomyces cerevisiae SUC2 gene upon derepression by glucose starvation. To gain further insight into the changes accompanying derepression at the chromatin level we have studied the chromatin structure of the SUC2 promoter in several mutants affecting SUC2 expression. The non-derepressible mutants snf1, snf2 and snf5 present a chromatin structure characteristic of the repressed state, irrespective of the presence or absence of glucose. The non-repressible mutants, mig1 and ssn6, as well as the double mutant snfs sn6 exhibit an opened chromatin structure even in the presence of glucose. Thes…
Comparative Transcriptomic Analysis Reveals Similarities and Dissimilarities in Saccharomyces cerevisiae Wine Strains Response to Nitrogen Availabili…
2015
Nitrogen levels in grape-juices are of major importance in winemaking ensuring adequate yeast growth and fermentation performance. Here we used a comparative transcriptome analysis to uncover wine yeasts responses to nitrogen availability during fermentation. Gene expression was assessed in three genetically and phenotypically divergent commercial wine strains (CEG, VL1 and QA23), under low (67 mg/L) and high nitrogen (670 mg/L) regimes, at three time points during fermentation (12 h, 24 h and 96 h). Two-way ANOVA analysis of each fermentation condition led to the identification of genes whose expression was dependent on strain, fermentation stage and on the interaction of both factors. The…
Molecular Characterization of New Natural Hybrids of Saccharomyces cerevisiae and S. kudriavzevii in Brewing▿ †
2008
ABSTRACT We analyzed 24 beer strains from different origins by using PCR-restriction fragment length polymorphism analysis of different gene regions, and six new Saccharomyces cerevisiae × Saccharomyces kudriavzevii hybrid strains were found. This is the first time that the presence in brewing of this new type of hybrid has been demonstrated. From the comparative molecular analysis of these natural hybrids with respect to those described in wines, it can be concluded that these originated from at least two hybridization events and that some brewing hybrids share a common origin with wine hybrids. Finally, a reduction of the S. kudriavzevii fraction of the hybrid genomes was observed, but th…
Diversity of yeast strains of the genus Hanseniaspora in the winery environment: What is their involvement in grape must fermentation?
2015
Isolated yeast populations of Chardonnay grape must during spontaneous fermentation were compared to those isolated on grape berries and in a winery environment before the arrival of the harvest (air, floor, winery equipment) and in the air through time. Two genera of yeast, Hanseniaspora and Saccharomyces, were isolated in grape must and in the winery environment before the arrival of the harvest but not on grape berries. The genus Hanseniaspora represented 27% of isolates in the must and 35% of isolates in the winery environment. The isolates of these two species were discriminated at the strain level by Fourier transform infrared spectroscopy. The diversity of these strains observed in t…
Physiological properties of some yeast strains
2006
Twenty yeast strains have recently been isolated in pure cultures from natural and industrial sources and identified based mainly on physiological properties. The majority of the strains (15) are alcohologenic belonging to the genus Saccharomyces and comprise two brewer's (beer) yeast strains (S. carlsbergensis= S. uvarum A and B), two baker's yeast strains (S. cerevisiae CA and CP), one spirit yeast strain (S. cerevisiae CF) and ten wine yeast strains (S. cerevisiae var. ellipsoideus = S. ellipsoideus 1, 3, 4, 6, 8 and 9; S. oviformis 2, 5 and 7; and S. uvarum 10). The other 5 yeast strains belong to different species: Kloeckera apiculate, Candida mycoderma (Mycoderma vini), Pichia membran…
Yeasts Isolated from the Alcoholic Fermentation ofAgave duranguensisDuring Mezcal Production
2013
Mezcal is a spirit produced in some regions of Mexico. In the state of Durango, mezcal is produced via traditional fermentation of the Agave duranguensis plant. To better understand traditional fermentation processes, it is necessary to know which yeast species are present in fermentations in different producer regions. The aim of this research was to study yeasts involved in traditional mezcal fermentation in Durango, Mexico, and investigate the phylogeny of the native Saccharomyces cerevisiae strains involved in this process. The 5.8S-ITS genomic region was analyzed to identify strains present in the fermentation process samples in this study. To differentiate strains belonging to the gen…
Saccharomyces cerevisiae glutaredoxin 5-deficient cells subjected to constitutive oxidizing conditions are affected in the expression of specific set…
2004
The Saccharomyces cerevisiae GRX5 gene codes for a mitochondrial glutaredoxin involved in the synthesis ofiron/sulfur clusters. Its absence prevents respiratory growth and causes the accumulation of iron inside cellsand constitutive oxidation of proteins. Null Δgrx5 mutants were used as an example of continuously oxidizedcells, as opposed to situations in which oxidative stress is instantaneously caused by addition of external oxidants.Whole transcriptome analysis was carried out in the mutant cells. The set of genes whose expression wasaffected by the absence of Grx5 does not significantly overlap with the set of genes affected in respiratorypetite mutants. Many Aft1-dependent genes involv…
Functional analysis of yeast gene families involved in metabolism of vitamins B1 and B6
2002
In order to clarify their physiological functions, we have undertaken a characterization of the three-membered gene families SNZ13 and SNO13. In media lacking vitamin B6, SNZ1 and SNO1 were both required for growth in certain conditions, but neither SNZ2, SNZ3, SNO2 nor SNO3 were required. Copies 2 and 3 of the gene products have, in spite of their extremely close sequence similarity, slightly different functions in the cell. We have also found that copies 2 and 3 are activated by the lack of thiamine and that the Snz proteins physically interact with the thiamine biosynthesis Thi5 protein family. Whereas copy 1 is required for conditions in which B6 is essential for growth, copies 2 and 3 …
Whole genome analysis of a wine yeast strain
2001
Saccharomyces cerevisiae strains frequently exhibit rather specific phenotypic features needed for adaptation to a special environment. Wine yeast strains are able to ferment musts, for example, while other industrial or laboratory strains fail to do so. The genetic differences that characterize wine yeast strains are poorly understood, however. As a first search of genetic differences between wine and laboratory strains, we performed DNA-array analyses on the typical wine yeast strain T73 and the standard laboratory background in S288c. Our analysis shows that even under normal conditions, logarithmic growth in YPD medium, the two strains have expression patterns that differ significantly …
De novo production of six key grape aroma monoterpenes by a geraniol synthase-engineered S. cerevisiae wine strain
2015
[Background] Monoterpenes are important contributors to grape and wine aroma. Moreover, certain monoterpenes have been shown to display health benefits with antimicrobial, anti-inflammatory, anticancer or hypotensive properties amongst others. The aim of this study was to construct self-aromatizing wine yeasts to overproduce de novo these plant metabolites in wines.